As shown in FIG. 1, a liquid crystal display (LCD) panel includes data lines and a data driving chip 30 that drives the data lines. The data driving chip 30 often employs a data driving unit 21 coupled to the data line to amplify driving ability of a signal, and the data driving unit 21 is configured with a first port and a second port, where a range of working voltage of the data driving unit 21 is determined by voltages input to the first port and the second port. Generally, a constant voltage is input to one of two ports of the data driving unit 21, and the constant voltage is regarded as a first reference voltage. Voltage input to a signal unit arranged external to the data driving chip 30 outputs voltage to the other port of the data driving unit 21, and the voltage is regarded as a second reference voltage. The second reference voltage directly affects stability of a data driving circuit, thus, the second reference voltage output by the signal unit is input to the data driving unit 21 through an isolation driving unit 10. The isolation driving unit 10 not only avoids load disturbance of the data driving unit 21 affecting, the signal unit of an input end of the data driving chip, but also improves driving ability of the second reference voltage. A typical method causes overheat of the data driving chip 30.